Intermittent input, average output types of pumps, also known as impulse pumps, have been known. Such pumps may have a movable pumping member that is moved to one position to load fluid into a pumping chamber and to another position to pump fluid from such pumping chamber. The loading action may occur in response to an intermittent work input, such as one derived using a solenoid and an electrical energy input, and the work output or pumping action may be effected by a spring or other work or energy storage device into which work (energy) had been stored during energization of, for example, the solenoid.
Various types of mechanical check valve arrangements have been used in the past to control the flow of fluid, vis-a-vis such prior pumps. Also, a movable contact arrangement was necessary to effect intermittent energization of the solenoid.
Some disadvantages encountered in the prior pumps of the subject type have been fluid leakage due to the multiple complex elements utilized and the relatively high cost also for the same reason. Furthermore, undesirable energy dissipation may occur in the prior pumps where the contact alignment is not maintained constant during multiple operations; accordingly, the contacts often become prematurely worn due to arcing and/or uneven current flow during multiple uses. Additionally, due to the frequent use of separate pump diaphragms, sealing gaskets, sealing measures taken at the check valves, etc., not only are the leakage and cost affected substantially, but the labor required to manufacture such prior pumps becomes excessive and expensive.